Party's Campaign Arm Targets Some Republicans That Are Backing a Broad Overhaul

WASHINGTON—House Democrats want to overhaul the nation's immigration system. They also want to take back their majority in 2014.

Those two goals have been at odds at times this summer. The Democratic Party's main campaign arm for House races is targeting 17 Republicans—the number of seats the party would need to flip to regain control—who it believes are vulnerable in 2014. More than half of those are also on the list of GOP lawmakers...